Alkali metal aluminates, such as sodium aluminate, are used industrially for hundreds of types of applications, for instance as coagulating agents in water clarification processes and as a papermaking additives. In many of such applications alkali metal aluminates are used as aqueous solutions and it is often preferable to prepare such solutions a significant time prior to use. Many industrial end-users in fact purchase such chemicals as aqueous solutions.
One disadvantage of such aqueous alkali metal aluminate solutions is that they may have a certain degree of instability. These products may crystalize and separate out of solution a number of weeks after preparation, which decreases the activity of the product and creates handling problems.
Stabilizing agents for aqueous alkali metal aluminate solutions known heretofore include a certain combination of tartaric and gluconic acids disclosed in U.S. Pat. No. 3,656,889. U.S. Pat. No. 2,345,134 discloses using a stabilizing agent which may consist of any one or combination of a number of substances such as Rochelle salts, tartaric acid and its salts, saccharates, gluconic acid and its salts, gallic acid and its salts, and other similar substances.
In the industrial chemical field not only is an improved stabilizer for aqueous alkali metal aluminate solutions desirable but also alternative stabilizers are desired. Given the vast number of applications in which alkali metal aluminates are presently used or may be used in the future, the potential for incompatibility of any given stabilizer with an in-use environment can never be reduced to zero.